Fig. 1. DNW phenotype is caused by abnormal subdivision along the PD and AP axis. Adult structures (A-F) and wing imaginal discs (G-K) of wild-type (C,D,G) and ds^38k mutant (A,B,E,F,H,I,J,K) specimens are shown. (A) Reduced wing (black arrowhead) associated with an ectopic notum (n'). (B) Magnification of an ectopic notum shows the scutum (sc) and scutelum (sct) structures next to a minimal winglet that is exclusively formed by a duplicated tegula (black arrowhead). (C) Wild-type hinge (square) and the wing blade regions divided by the AP boundary (black line). The asterisk marks the position of the anterior wing margin. (D) High magnification view of the hinge in C, showing anterior proximal structures such as the tegula (tg), humeral sclerite (hsc) and costa (co). (E) Detail of a winglet composed of anterior proximal structures arranged in a mirror-image duplication. (F) Detail of a rudimentary wing blade in which only anterior wing margin bristles (normally formed at the position marked by the asterisk in C) are present. (G) Third instar wild-type discs stained for (a) Nub (green) and Iro (red) to delimit the territories along the PD axis. wp, wing pouch; n, notum. The AP and DV compartments are marked by (b) Ci (red) and Wg (green); (c) En (green) and Vg (red); and (d) En (green) and Ap (red). The white line highlights the border between the A and P compartments. (H-K) Late DNW wing discs show (H) a reduced wing pouch (Nub; green) and an expansion of the notum territory (n and n') (Iro; red). (I) The notal duplication, visualised by a double notal band of Wg (green), is expanded into the hinge territory and is formed by A (Ci; red) and P cells. (J) P cells (En; green) are only present in the notum territory. The wing pouch (Vg; red) cells are confined in the A compartment. The inset in J represent early discs of wild-type (left) and ds^38k (right) larvae. The comparison shows that the DNW phenotype occurs very early. The dorsal (red) and ventral compartments are apparently normal (K).